Better Fat Than Unfit
The 2018 JAMA special issue on obesity also includes a brief paper by Ann Blair Kennedy and colleagues reviewing the debate (which really isn’t much of a debate to anyone who knows the data) on whether it is more important to be fit than to worry about being fat (it is). As the authors review, there is now ample data showing that cardio-respiratory fitness (CRF) is far more important for the prediction of cardiovascular mortality than the level of fatness (measured as BMI or otherwise). In fact, once you account for differences in “fitness”, actual BMI levels almost cease to matter in terms of predicting longevity. Unfortunately, as the authors point out, most studies linking obesity to cardiovascular outcomes (including studies on the so-called obesity “paradox”), fail to properly measure or account for cardiovascular fitness, thereby ignoring the most important confounder of this relationship. For clinicians (and anyone concerned about their excess weight), it is helpful to remember that while achieving and maintaining a significant weight loss is a difficult (and often futile) undertaking, achieving and maintaining a reasonable degree of cardiorespiratory fitness is possible at virtually any shape or size. Thus, as the authors point out, “…in current US society, many people progressively gain weight and lose CRF as they age. Conceivably, maintaining CRF may be more important than preventing the development of obesity. However, for people who are overweight or have mild to moderate obesity, there are effective ways to improve CRF, including exercise and lifestyle interventions and there is general agreement that having low levels of PA is unhealthy. Increasing PA to help keep individuals from becoming unfit can be achieved if patients meet current PA guidelines of 150 minutes of moderate or 75 minutes of vigorous PA per week.” Clearly, if your primary concern related to your patients’ excess body fat is about their cardiovascular health, you would probably be doing them a far greater service by getting them to improve their cardiorespiratory fitness rather than simply lose a few pounds (and no, exercise is not the best way to lose weight!). On the other hand, if there are other health issues that are of primary concern (e.g. sleep apnea, osteoarthritis, fatty liver disease, etc.) or the degree of excess fat significantly affects mobility or other aspects of quality of life, then perhaps a frank discussion about available and effective “weight-loss” treatments appears warranted. Let us not… Read More »
The OPQRST Of Body Weight
The assessment of weight history is no doubt a key feature of obesity assessment. Not only can weight history and trajectories provide important insights into obesity related risk but, perhaps more importantly, provide key information on precipitating factors and drivers of excessive weight gain. Now, in a short article published in MedEdPublish, Robert Kushner discusses how the well-known OPQRST mnemonic for assessing a “chief complaint” can be applied to assess body weight. In short, OPQRST is a mnemonic for Onset, Precipitating, Quality of Life, Remedy, Setting, and Temporal pattern. Applied to obesity, Kushner provides the following sample questions for each item: Onset: “When did you first begin to gain weight?” “What did you weight in high school, college, early 20s, 30s, 40s?” “What was your heaviest weight?” Precipitating: “What life events led to your weight gain, e.g., college, long commute, marriage, divorce, financial loss?” “How much weight did you gain with pregnancy?” “How much weight did you gain when you stopped smoking?” “How much weight did you gain when you started insulin?” Quality of life: “At what weight did you feel your best?” “What is hard to do at your current weight?” Remedy: “What have you done or tried in the past to control your weight?” “What is the most successful approach you tried to lose weight?” “What do you attribute the weight loss to?” “What caused you to gain your weight back?” Setting: “What was going on in your life when you last felt in control of your weight?” “What was going on when you gained your weight?” “What role has stress played in your weight gain?” “How important is social support or having a buddy to help you?” Temporal pattern: “What is the pattern of your weight gain?” “Did you gradually gain your weight over time, or is it more cyclic (yo-yo)?” “Are there large swings in your weight, and if so, what is the weight change?” As Kushner notes, “These features provide a contextual understanding of how and when patients gained weight, what efforts were employed to take control, and the impact of body weight on their health. Furthermore, by using a narrative or autobiographical approach to obtaining the weight history, patients are able to express, in their own words, a life course perspective of the underlying burden, frustration, struggle, stigma or shame associated with trying to manage body weight. Listening should be unconditional and nonjudgmental. By letting patients tell their story, the… Read More »
How The Body Weighs Itself – Evidence For A Bone “Gravitostat”
In my talks, I have often joked about how to best keep weight off – just carry around a backpack that contains the lost pounds to fool the body into thinking the weight is still there. It turns out that what was intended as a joke, may in fact not be all too far from how the body actually regulates body weight. As readers of these posts are well aware, body weight is tightly controlled by a complex neuroendocrine feedback system that effectively defends the body against weight loss (and somewhat, albeit less efficiently, protects against excessive weight gain). Countless animal experiments (and human observations) show that following weight loss, more often than not, body weight is regained, generally precisely to the level of initial weight. With the discovery of leptin in the early 90s, an important afferent part of this feedback system became clear. Loss of fat mass leads to a substantial decrease in leptin levels, which in turn results in increased appetite and decreased metabolic rate, both favouring weight regain and thus, restoration of body weight to initial levels. Now, an international team of researchers led by John-Olov Jansson from the University of Gothenburg, Sweden, in a paper published in the Proceeding of the National Academy of Science (PNAS), provides compelling evidence for the existence of another afferent signal involved in body weight regulation – one derived from weight-bearing bones. Prompted by observations that prolonged sedentariness can promote weight gain, independent of physical activity, the researchers hypothesised that, “…there is a homeostat in the lower extremities regulating body weight with an impact on fat mass. Such a homeostat would (together with leptin) ensure sufficient whole body energy depots but still protect land-living animals from becoming too heavy. A prerequisite for such homeostatic regulation of body weight is that the integration center, which may be in the brain, receives afferent information from a body weight sensor. Thereafter, the integration center may adjust the body weight by acting on an effector.” In a first series of experiments, the researchers observed that implanting a weight corresponding to about 15% of body weight into rodents (rats and mice), resulted in a rapid “spontaneous” adjustment in body weight so that the combined weight of the animal plus the weight implant corresponded more-or-less to that of control animals. Within two weeks of implanting the weights, ∼80% of the increased loading was counteracted by reduced… Read More »
Preventing and Managing Childhood Obesity
This morning, I am presenting a plenary talk in Berlin to about 200 colleagues involved in childhood obesity prevention. The 1-day symposium is hosted by Plattform Ernährung und Bewegung e.V. (Platform for Nutrition and Physical Activity), a German consortium of health professionals as well as public and private stakeholders in public health. Although, as readers are well aware, I am by no means an expert on childhood obesity, I do believe that what we have learnt about the complex socio-psycho-biology of adult obesity in many ways has important relevance for the prevention and management of childhood obesity. Not only do important biological factors (e.g. genetics and epigenetics) act on the infant, but, infants and young children are exposed to the very same societal, emotional, and biological factors that promote and sustain adult obesity. Thus, children do not grow up in isolation from their parents (or the adult environment), nor do other biological rules apply to their physiology. It should thus be obvious, that any approach focussing on children without impacting or changing the adult environment will have little impact on over all obesity. This has now been well appreciated in the management of childhood obesity, where most programs now take a “whole-family” approach to addressing the determinants of excess weight gain. In fact, some programs go as far as to focus exclusively on helping parents manage their own weights in the expectation (and there is some data to support this) that this will be the most effective way to prevent obesity in their offspring. As important as the focus on childhood obesity may be, I would be amiss in not reminding the audience that the overwhelming proportion of adults living with obesity, were normal weight (even skinny!) kids and did not begin gaining excess weight till much later in life. Thus, even if we were somehow (magically?) to completely prevent and abolish childhood obesity, it is not at all clear that this would have a significant impact on reducing the number of adults living with obesity, at least not in the foreseeable future. Let us also remember that treating childhood obesity is by no means any easier than managing obesity in adults – indeed, one may argue that effectively treating obesity in kids may be even more difficult, given the the most effective tools to managing this chronic disease (e.g. medications, surgery) are not available to those of us involved in… Read More »
Why Would Anyone Want Access to Prescription Medications For Obesity?
Just imagine if the question in the title of this post was, “Why would anyone want access to prescription medications for diabetes?” (or heart disease? or lung disease? or arthritis? or, for that matter, cancer?) Why would anyone even ask that question? If there is one thing we know for sure about obesity, it is that it behaves just like every other chronic disease. Once you have it (no matter how or why you got it) – it pretty much becomes a life-long problem. Our bodies are so efficient in defending our body fat, that no matter what diet or exercise program you go on, ultimately, the body wins out and puts the weight back on. In those few instances where people claim to have “conquered” obesity, you can virtually bet on it, that they are still dealing with keeping the lost weight off every single day of their life – they are not cured, they are just treated! Their risk of putting the weight back on (recidivism) is virtually 100% – it’s usually just a matter of time. Funnily enough, this is no different from people trying to control any other chronic disease with diet and exercise alone. Take for e.g. diabetes. It is not that diet and exercise don’t work for diabetes, but the idea that most people can somehow control their diabetes with diet and exercise alone is simply not true. No matter what diet they go on or what exercise program they follow, sooner or later, their blood sugar levels go back up and the problems come back. You could pretty much say the same for high blood pressure or cholesterol, or pretty much any other chronic health problem (that, in fact, is the very definition of “chronic”). So why medications for obesity? Because, like every other chronic disease, medications can help patients achieve long-term treatment goals (of course only as long as they stay on treatment). Simply put, if the reason people virtually always regain their lost weight (no matter how hard they try to lose it) is simply because of their body’s ability to resist weight loss and promote weight regain, then medications that interfere with the body’s ability to resist weight loss and promote weight regain, will surely make it far more likely for them to not only lose the weight but also keep it off. Now that we increasingly understand many of the body’s mechanisms to defend… Read More »
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